1. Technical Field
The present invention is related generally to a hot stretch forming die and a method of using the same. More particularly, the invention relates to such a die which is configured to minimize the distortion of the die due to thermal expansion during the process of forcing a heated metal work piece against the die face. Specifically, the invention relates to such a die which also includes an adjustable die face to allow for the adjustment of the contour of the die.
2. Background Information
It is well known in the art of hot stretch forming to wrap a heated metal bar around the work surface or die face of a rigid die in order to bend the metal bar into a shape conforming to the contour of the die face. However, one of the problems that arises during this process is the thermal expansion of the die as heat is transferred from the metal bar to the die face and the rest of the die. Because there is a need to maintain an accurate shape or contour of the die during the hot stretch forming of the part, this thermal expansion of the die is normally significant enough to present a problem in controlling the resulting contour of the shaped metal bar. In addition, there is a need in the art to produce a final part which is within fairly close tolerances. Due to the difficulty in controlling various factors such as the precise temperature of the metal bar during the forming process and the fact that the part shrinks after the forming process as the part cools down, there are typically some trial and error corrections made to the die face or other aspects of the process in order to produce parts within the defined tolerances. This trial and error process may involve the production of an initial part by the hot forming process, testing to determine where the final part is out of tolerance, and the grinding of the die face in certain areas in order to provide the appropriate contour which will result in a subsequent part within the given tolerances. The present invention addresses these and other issues in the art.